Standardization of Encapsulation Technique for Producing Synthetic Seeds in Coffee

Abstract

Seeds are the primary means of propagation in many crops. The use of genetically uniform tissue culture derived plants could be considered advantageous for crops such as coffee, in which vegetative propagation is difficult to practice. Micropropagation technique is greatly constrained due to high cost involved and inadequate standardization of hardening procedure. During transfer of plants from laboratory to field, generally high mortality rates result that further lower the efficacy of results achieved in-vitro (Mathur et al., 1989). For these reasons, efforts have been made to overcome the constraints by encapsulating somatic embryos (Kitto and Janick, 1985; Redenbaugh et al., 1987) in different matrices and to grow them on different media. Studies on somatic embryogenesis and related encapsulation of somatic embryos have been reported by Redenbaugh et al. (1993). The first successful examples of synthetic seed technology were in alfalfa and celery. Fujii et al. (1989) grew plants at low frequency from synthetic seeds of alfalfa, planted directly in the field. Kirin Brewery Co Ltd., Japan and Plant Genetics Inc., USA conducted field trails in Japan with 20,000 F₁ synthetic seeds in 1988 (Sanada et al., 1993). Recently, Rao et al. (1998) reviewed the concept, methods and micropropagation as well as germplasm conservation through preservation of encapsulated zygotic and somatic embryos in liquid nitrogen. In coffee, somatic embryogenesis has been achieved from different tissues (Sondahl and Loh, 1988; Sreenath and Naidu, 1997; Muniswamy and Sreenath, 1997). However, reports on encapsulation and subsequent plant regeneration for producing synthetic seeds in coffee are very much limited. Here we report plant regeneration from encapsulated zygotic and somatic embryos of coffee.